Method of producing nibs for writing instruments

ABSTRACT

This invention is to produce, on a mass-production scale and at low cost, the nibs or pen points for various types of writing pens which permit smooth writing performance with always constant size for a long period of use.

United States Patent Inventor Takaji Funahashi No. 1, Z-chome, Kitatkajo-machi, Nishi-ku, Nagoya-shi, Aichi-ken, Japan App]. No. 826,615 Filed May 21, 1969 Patented Dec. 14, 1971 Priorities May 24, 1968 Japan 43142795;

May 24, 1968, Japan, No. 43/42796; June 6, 1968, Japan, No. 43/47470; Aug. 14, I968, Japan, No. 43/57912 METHOD OF PRODUCING NIBS FOR WRITING INSTRUMENTS 8 Claims, 41 Drawing Figs.

U.S. CL; 264/250, 264/274, 264/242, 264/171 Int. Cl 829d 9/00 Field of Search 264/ 1 7 l [56] References Cited UNITED STATES PATENTS 3,364,002 1/1968 Michel 2,565,316 8/1951 Lucas 1,978,163 10/1934 Megow... 3,387,069 6/1968 Stohr 2,938,566 5/1960 Toulmin. 3,267,075 8/1966 Schnell 3,078,248 2/1963 Ben 2,930,083 3/1960 Vostovich. 3,406,248 10/ l 968 Bunish Primary Examiner-Donald .1. Arnold Assistant Examiner-Thomas Pavelko Anorney-Waters, Roditi, Schwartz & Nissen 264/274 X 264/249 X 264/171 X 264/154 X 264/174 X 264/176 X 264/176 X ABSTRACT: This invention is to produce, on a muss-production scale and at low cost, the nibs or pen points for various types of writing pens which permit smooth writing performance with always constant size for a long period of use.

PATENTEDuEcMmn v 3,627, 8

' SHEET 3 [1F 4 METHOD OF PRODUCING NIBS FOR WRITING INSTRUMENTS This invention relates to a method of producing nibs or pen points used in writing instruments popularly called as felt pen, sign pen, marker or in other names.

The conventional nibs for writing instruments of this kind are usually made by longitudinally bundling the single fibers of primarily synthetic fibers or wool fibers, then solidifying the bundle with a therrnosetting resin in a capillary-formed condition, and shaving the end thereof to point it, However, such nib may become defon-ned since the fibers at the pointed end get loose gradually during use of it as it is pressed against a paper or the like for writing purpose, thus making it finally hardly possible to perfonn correct writing, particularly when the nib is designed for slender writing. To cope with such defect, it may be suggested to increase hardness of the nib by using a large amount of thermosetting synthetic resin. However, such practice will inevitably result in retarded capillary action of the fibers and poor ink-oozing function, hence inability to carry on correct and proper writing.

This invention is designed to sweep away these defects inherent to the conventional nibs of writing instruments of this type, an object of this invention is to produce, on a massproduction scale and at low cost, the nibs or pen points for various types of writing pens which permit smooth writing performance with always constant size for a long period of use.

Another object of this invention is to provide the nibs or pen points of said character in which a fine rod element which corresponds to a nib is composed of a synthetic resin material having small frictional resistance and excellent wear resistance, such as polyacetal resin, polycarbonate resin or polyamide resin, so that the produced nibs, even if designed for slender writing, can stand a long time use while maintaining a constant size of written characters or letters.

Still another object of this invention is to provide a nib in which a fine rod element which corresponds to a nib is formed of a synthetic resin material such as polyacetal resin, polycarbonate resin or polyamide resin, and an outer sheath which sheathes said fine rod element is composed of a thermoplastic resin material such as polyethylene resin or polypropylene resin, and in which the slits permitting a suitable amount of ink to ooze are formed between the rod element and the sheath by dint of the difference of contraction between said both synthetic resin materials when they are shaped. Now, some preferred embodiments of this invention will be described in detail with reference to the accompanying drawings, wherein:

FIGS. 1 to 8 illustrate a first embodiment of this invention, in which FIG. I is a partial perspective view of a fine elongated rod element according to this invention;

FIG. 2A is a sectional view as taken on the line IIII of FIG.

FIG. 2B is a similar sectional view of a modified form of said rod element;

FIGS. 3 and 4 are respectively a partial perspective view of two difierent types of elongated nibs formed by covering said rod element with a sheath;

FIGS. 5 and 6 are the sectional views as taken on the line V-V of FIG. 3 and the line VI-VI of FIG. 4, respectively;

and FIGS. 7 and 8 show the perspective views of two different types of nibs according to this invention, with FIG. 7A and FIG. 8A showing a case in which the sheath is of a columnar configuration and FIG. 7B and FIG. 88 showing a case in which the sheath is of a square pillarlike configuration.

FIGS. 9 to 17 illustrate a second embodiment of this invention in which FIG. 9 is a partial perspective view of an elongated rod element;

FIG. 10A is a sectional view as taken on the line X-X of FIG. 9;

FIG. 10B is a similar sectional view of a modified form of the rod element;

FIG. 11 is a partial perspective view, a part being broken away, of a sheath member;

FIG. 12 is a sectional view as taken on the line XII-XII of FIG. 11;

FIG. 13 is a partial perspective view showing a condition in which an elongated rod element is being loosely inserted into a sheath member;

FIG. 14 is a sectional view as taken on the line XIV-XIV of FIG. 13;

v FIG. 15 is a partial perspective view of a nib obtained after passing the sheath having inserted therein an elongated rod element through a heating die;

FIG. 16 is a sectional view as taken on the line XVI-XVI of FIG. 15;

and FIG. 17 shows perspective views of the obtained products, with FIG. 17A showing a case in which the outer periphery of the sheath is flat and FIG. 17B showing a case in which fine grooves are formed in the axial direction on the outer periphery of the sheath.

FIGS. 18 to 26 illustrate a third embodiment of this invention in which FIG. 18 is a perspective view of a nib which is petal-shaped in section;

FIG. 19 is a sectional view as taken on the line XIX-XIX of FIG. 18; v

FIG. 20 is a perspective view of a nib which is of a corrugated radial configuration in section;

FIG. 21 is a sectional view as taken on the line XXI-XXI of FIG. 20;

FIG. 22 is a perspective view of a nib which is star-shaped in section;

FIG. 23 is a sectional view as taken on the line XXIII- XXIII of FIG. 22;

FIG. 24 is a sectional view of a nib which is petal-shaped in section and has small grooves formed longitudinally on the external surface thereof;

FIG. 25 is a sectional view of a nib having a corrugated radial configuration in section, with small grooves being formed longitudinally on the outer surface thereof;

and FIG. 26 is a sectional view of a nib which is star-shaped in section and has small longitudinal grooves on the outer surface thereof.

FIGS. 27 to 30 illustrate a fourth embodiment of this invention, in which FIG. 27 is a perspective view of a nib which is petal-shaped in section and has a central hole in the elongated rod element in the inside thereof;

FIG. 28 is a sectional view as taken on the line XXVIII XXVIII of FIG. 27;

FIG. 29 is a perspective view of a nib having a petal-shaped section, with fibrous material being inserted into the rod element in the inside thereof;

and FIG. 30 is a sectional view as taken on the line XXX- XXX of FIG. 29.

FIG. 31 to 34 illustrate a fifth embodiment of this invention, in which FIG. 31 is a fragmentary perspective view, a part being broken away, of a nib in which an elongated rod element having tooth-sectioned grooves is forcibly inserted into a columnar sheath member;

FIG. 32A is a sectional view as taken on the line XXXII- XXXII ofFIG. 31;

FIG. 32B is a similar sectional view of a modified form of the rod-sheath assembly;

FIG. 33 is a fragmentary perspective view, a part being broken away, of a nib in which a columnar rod element is forcibly inserted into the inside of a sheath having on its inner surface the tooth-sectioned grooves;

FIG. 34A is a sectional view as taken on the line XXXIV- XXXIV of FIG. 33;

and FIG. 34B is a similar sectional view of another form of the rod-sheath assembly.

EXAMPLE 1 Referring to FIGS. 1 to 3. 5 and 7, an elongated rod member 2 which is columnar in section and has radially extended vane plates I having thereon longitudinally extending grooves 3 is formed from polyamide resin having a melting point of approximately 260 C. by extrusion molding. Then, this elongated rod member 2 is passed through a crosshead die of the extrusion molding machine while forming a sheath member 4 having a similar columnar section with polypropylene resin having a melting point of approximately 176 C., and the extrusion is immediately passed through cold water of less than about 10 C. to thereby cool and solidify it. The obtained product is then cut into a desired length (about 3 cm.) for a required nib and the end thereof is either subjected to a grinder or other machining means to be thereby sharpened into a conical or otherwise contoured pen point 8 or pressed into a hot mold of a desired configuration having a temperature of approximately 176 C. to thereby obtain a desired pen point or nib. In this case, longitudinal grooves 7 may be conveniently provided on the peripheral surface of the sheath member 4, as shown in FIGS. 4, 6 and 8, so as to increase the oozing amount of ink to attain the same effect as described above. In the case of example 1, even if the radially extended vane plates 1 on the rod member 2 are formed as flat plates as shown by 2' (see FIG. 28), it is also possible to obtain the ink oozing grooves of a suitable size between the rod 2 and the sheath 4 owing to difference of contraction between said both members. In the embodiment shown in FIGS. 1 to 8, both rod member 2 and sheath 4 are shown as having a columnar sectional configuration, but they may also be arranged to have a triangular, quadrilateral (see FIG. 7B and FIG. 8B or polygonal prism-, petalor star-shaped sectional configuration to obtain the same action and efiect.

EXAMPLE 2 Referring to FIGS. 9 to 14 and 17 A, polycarbonate resin having a melting point of approximately 220 C. is subjected to extrusion molding to obtain an elongated rod member 2a which is columnar in section and has formed therearound radially extended vane plates la thereon indented grooves 3a extending vertically in the axial direction. Likewise, polyethylene resin having a melting point of approximately 137 C. is subjected to extrusion molding to form a sheath member 4a which is columnar is section and has a central through-hole a including radial slits each running vertically in the axial direction. Said elongated rod member 2a is loosely inserted into the central hole 50 of said sheath 4a and passed through a heating die at a temperature somewhat higher than the melting temperature of the sheath 4a so that the rod member 2a is covered with the sheath 4a, and immediately thereafter, the assembly is passed though cold water of less than about C. to cool it thereby obtaining a desired nib 8a in the otherwise same manner as in example 1. In this case, as shown in FIGS. I5, 16 and 17B, fine grooves 7a may be formed on the peripheral surface of the sheath 4a through the nozzle of cross head die having the form of corresponding grooves so as to increase the oozing amount of ink, in which case the same action and effect as described above may be obtained. Also, even if the radially extended vane plates 10 of the elongated rod member 20 may be formed from flat plates as indicated by 2'a (see FIG. 108) the same effect as in the above-described case of example 2 will be attained.

EXAMPLE 3 Referring to FIGS. 18 and 19, first polyamide resin having a melting point of approximately 260 C. is subjected to extrusion molding to form a columnar elongated rod member 2b which is petal-shaped in section. Then, this elongated rod member 2b is loosely inserted into a columnar sheath member 4b which is made of polypropylene resin having a melting point of approximately 176 C. and petal-shaped in section and which has also a central through-hole 5b having a larger diameter than the outer diameter of said rod member 2b, and the assembly is then formed through a bell-shaped die heated at a temperature somewhat lower than the melting point of said sheath member 4b, thereby to fit the rod member 2b in the sheath 4b. Then, immediately thereafter, the product is passed through cold water of less than about 10 C. to cool it, thus obtaining a desired nib 8b in the same manner as in the preceding examples. FIGS. 20 and 21 show anembodiment in which the elongated rod member 2c and the sheath member 4c are both columnar in external shape and corrugate radialshaped in section, while shown in FIGS. 22 and 23 is a modified case where the rod member 2d and the sheath member 4d are columnar in external shape but radially extending star-shaped in section.

FIGS. 24, 25 and 26 show the cases where fine grooves 72, 7f and 7g, respectively, are provided on the outer surfaces of the sheathes 4e, 4f and 4g coated on the elongated rod members 2e, 2f and 2g, respectively.

In this is example, the central through-holes 5b-5g of the sheathes 4b-4g, respectively, are formed somewhat smaller than the contours of the elongated rod members 2b-2g, and the rod-sheath assembly is heated to a temperature slightly lower than the melting point of said sheath materials 4b-4g, thereby causing the rod members 2b-2g to be closely fitted in the respective central-holes 55-53 of the sheath members, and then is immediately cooled in cold water of less than about l0 C., whereby small spaces are formed between the rod and the sheath due to difference of their contraction, and thus ob tained is a nib similar to those produced in examples l and 2.

EXAMPLE 4 Referring to FIGS. 27 to 30, there is shown in a specific embodiment which is designed to control the oozing amount of ink according to viscosity, driability and other properties of the particular ink to be used. FIGS. 27 and 28 embodies a construction where the axial holes 9 are formed are formed by extrusion molding in the center of either of the elongated rod members 2-2g in the preceding examples l-3, so as to obtain better capillary action.

Embodied in FIGS. 29 and 30 is a case where an elongated fibrous material 10 is inserted in said hole 9 by means of the extrusion to facilitate the capillary action. This fibrous material 10 must be the one which is neither melted nor affected in quality and shape when exposed to the extrusion-molding temperature.

EXAMPLE 5 Referring to FIGS. 31 and 32, an elongated rod member 2h having tooth-sectioned grooves 3h is formed by extrusionmolding of polyamide resin having a melting point of approximately 260 C., and the obtained rod is forcibly inserted into a circular sheath 4h molded from polypropylene resin having a melting point of approximately 176 C. Then, the same finishing process as in the previous examples is applied to obtain a desired nib 8h. In this case, it is to be noted that a small axial hole 9): is provided in the center of the elongated rod member 2h in conformity to viscosity,-driability and other properties of the ink used, as shown in FIG. 32B, thereby to better capillary action of the nib.

Referring now to FIGS. 33 and 34, there is shown still another embodiment in which said sheath d'h is formed such as to have a tooth-shaped inner sectional configuration 3'h and an elongated rod member 2'h having a circular sectional contour is forcibly pressed into the inside of said sheath 4h, and then the same finishing means as in the preceding examples is adopted to produce a desired nib 8h. In this case, a small axial hole 9h is provided in the center of the rod member 2'h as shown in FIG. 34B, thereby to expedite capillary action of the nib in conformity to the type of ink used.

This invention has been described by way of its preferred five examples, but it is to be understood that the present invention is not limited to the particular examples shown and described above but many variations may be made without departing from the spirit and scope of the invention which is defined only by the appended claims.

What we claim is:

l. A method of producing a nib for a writing instrument or the like, comprising molding an elongated rod member having a plurality of vane plates extended radially relative to the axis thereof with a synthetic resin material selected from the group consisting essentially of polyacetal, polycarbonate, and polyamide having a relatively high melting point and excellent wear resistance, molding around said rod member a sheath molded from a thermoplastic synthetic resin material selected from the group consisting essentially of polyethylene and polypropylene having a lower melting point than that of the first-said resin material, and then cooling the whole structure so as to form small gaps extending in the axial direction between the vane plate faces of said elongated rod member and the sheath.

2. A method according to claim 1, in which said plurality of radial vane plates are shaped such that their cross section is columnar, trigonal prism-shaped, quadrangular prism-shaped, polygonal prism-shaped, petal-shaped or star-shaped.

3. A method according to claim 1, in which said plurality of radial vane plates are platelike or corrugate in contour.

4. A method according to claim 3, in which said plurality of radial vane plates are provided on their surface with indented grooves in the axial direction.

5. A method according to claim 1, in which said elongated rod member is arranged such that its external contour corresponds substantially with the inside configuration of the sheath.

6. A method according to claim 1, in which suitable slits are formed on the peripheral surface of said sheath.

7. A method according to claim 5, in which a small axial hole is formed in the center of said elongated rod member.

8. A method according to claim 5, in which an elongated fibrous material is inserted axially in the center of said elongated rod member.

I i I IF t 

2. A method according to claim 1, in which said plurality of radial vane plates are shaped such that their cross section is columnar, trigonal prism-shaped, quadrangular prism-shaped, polygonal prism-shaped, petal-shaped or star-shaped.
 3. A method according to claim 1, in which said plurality of radial vane plates are platelike or corrugate in contour.
 4. A method according to claim 3, in which said plurality of radial vane plates are provided on their surface with indented grooves in the axial direction.
 5. A method according to claim 1, in which said elongated rod member is arranged such that its external contour corresponds substantially with the inside configuration of the sheath.
 6. A method according to claim 1, in which suitable slits are formed on the peripheral surface of said sheath.
 7. A method according to claim 5, in which a small axial hole is formed in the center of said elongated rod member.
 8. A method according to claim 5, in which an elongated fibrous material is inserted axially in the center of said elongated rod member. 